Technical Parameters Parameter Category Specification Product Series / Platform ABB Relion® 615 Series (REF615 Platform) Device Type Numerical Feeder Protection and Control Relay (IED) Hardware Variant Suffix -D - Defines the auxiliary power supply range: 48-110 V DC. Key Standards IEC 60255, IEC 61850 (Ed. 2), IEC 60870-5-103 Rated Auxiliary Supply (Us) 48 - 110 V DC (This is the defining characteristic of the -D version). Analog Inputs • Current (CT) Inputs 5 current inputs (3 phase + 1 neutral + 1 sensitive earth). Configurable for 1 A or 5 A secondary. • Voltage (VT) Inputs 4 voltage inputs (3 phase + 1 residual). Typical ratings: 100/110 V or 100/√3 V. Core Protection Functions Comprehensive suite (software-configurable): • Directional/Non-directional overcurrent (50/51, 67) • Earth-fault protection (50N/51N, 67N) • Negative sequence overcurrent (46) • Thermal overload (49) • Over/Under voltage (27/59) & frequency (81) • Auto-reclosing (79) • Circuit breaker failure (50BF) Control & Automation • Control of switching devices (CB, disconnectors). • Programmable logic (CFC). • Synchrocheck (25). Measurement & Metering Class 0.5 for I, V, P, Q, S, PF, f, Energy, Harmonics. Human-Machine Interface (HMI) • Graphical LCD with backlight. • Keypad. • LED indicators. • Front USB port. Data Recording • Event recorder. • Disturbance recorder (fault oscillography). Communication Interfaces Base unit typically includes: • 1 x RS485 port (for IEC 60870-5-103 / Modbus RTU). • 1 x Ethernet port (RJ45). Optional plug-in modules for IEC 61850, IEC 60870-5-104, etc. Time Synchronization Supports IRIG-B, SNTP. Operating Temperature Standard Range: -25°C to +55°C (or -40°C to +70°C depending on specific -D variant; refer to datasheet). Mounting Panel-mounted. Configuration Software ABB PCM600. Typical Ordering Code A full code is longer, e.g., REF615C-D A5D1A1B1B1B5C..., specifying CT/VT ratings, I/O, and communication options.